Securities - Schedule of Available for Sale Securities in an Unrealized Loss Position (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Held-to-maturity securities:
Temporarily impaired securities, fair value, less than 12 months	$ 15,728	$ 2,055
Temporarily impaired securities, gross unrealized losses, less than 12 months	281	79
Temporarily impaired securities, fair value, 12 months or longer	22,010	41,416
Temporarily impaired securities, gross unrealized losses, 12 months or longer	3,906	5,970
Temporarily impaired securities, fair value	37,738	43,471
Temporarily impaired securities, gross unrealized losses	4,187	6,049
U.S. Treasury, agencies and corporations
Securities available for sale:
Fair value, less than 12 months	3,647	0
Gross unrealized losses, less than 12 months	8	0
Fair value, 12 months or longer	508	8,532
Gross unrealized losses, 12 months or longer	36	280
Fair value, total	4,155	8,532
Gross unrealized losses, total	44	280
Agency residential collateralized mortgage obligations
Securities available for sale:
Fair value, less than 12 months	91	0
Gross unrealized losses, less than 12 months	0	0
Fair value, 12 months or longer	8,108	14,979
Gross unrealized losses, 12 months or longer	2,193	3,437
Fair value, total	8,199	14,979
Gross unrealized losses, total	2,193	3,437
Held-to-maturity securities:
Fair value, less than 12 months	569	1,123
Gross unrealized losses, less than 12 months	18	30
Fair value, 12 months or longer	3,387	3,070
Gross unrealized losses, 12 months or longer	314	253
Fair value, total	3,956	4,193
Gross unrealized losses, total	332	283
Agency residential mortgage-backed securities
Securities available for sale:
Fair value, less than 12 months	11,364	24
Gross unrealized losses, less than 12 months	254	0
Fair value, 12 months or longer	3,145	3,562
Gross unrealized losses, 12 months or longer	618	600
Fair value, total	14,509	3,586
Gross unrealized losses, total	872	600
Held-to-maturity securities:
Fair value, less than 12 months	0	0
Gross unrealized losses, less than 12 months	0	0
Fair value, 12 months or longer	134	152
Gross unrealized losses, 12 months or longer	17	13
Fair value, total	134	152
Gross unrealized losses, total	17	13
Agency commercial mortgage-backed securities
Securities available for sale:
Fair value, less than 12 months	50	891
Gross unrealized losses, less than 12 months	1	49
Fair value, 12 months or longer	4,360	8,201
Gross unrealized losses, 12 months or longer	516	1,154
Fair value, total	4,410	9,092
Gross unrealized losses, total	517	1,203
Held-to-maturity securities:
Fair value, less than 12 months	0	0
Gross unrealized losses, less than 12 months	0	0
Fair value, 12 months or longer	2,060	2,199
Gross unrealized losses, 12 months or longer	203	204
Fair value, total	2,060	2,199
Gross unrealized losses, total	203	204
Asset-backed securities
Held-to-maturity securities:
Fair value, less than 12 months	0	0
Gross unrealized losses, less than 12 months	0	0
Fair value, 12 months or longer	300	709
Gross unrealized losses, 12 months or longer	8	29
Fair value, total	300	709
Gross unrealized losses, total	8	29
Other securities
Held-to-maturity securities:
Fair value, less than 12 months	7	17
Gross unrealized losses, less than 12 months	0	0
Fair value, 12 months or longer	8	12
Gross unrealized losses, 12 months or longer	1	0
Fair value, total	15	29
Gross unrealized losses, total	$ 1	$ 0